The present invention relates to processes for recycling scrap tires. More particularly the present invention relates to processes for treating scrap tires to remove inorganic components, steel belts and to convert the tires to rubber particles.
Currently, about 200 million scrap tires are being stockpiled, landfilled or illegally dumped annually with about 50 million scrap tires being recycled in a variety of ways. The current disposal methods are causing numerous short term environmental problems. For example, whole tires occupy large amounts of space and may "float" or rise to the top of landfills. In an attempt to prevent floating, many landfills require that scrap tires be shredded, a process which is energy intensive and wasteful if it does not produce any useful product.
Scrap tire stockpiles produce health risks by providing a place for rodents and mosquitoes to breed which facilitates the spreading of diseases. Large fires have also broken out in scrap tire stockpiles causing many problems. These fires are long lasting and are difficult to extinguish, unnecessarily tying up fire fighting resources. Additionally, these fires produce unwanted smoke which pollutes the environment and toxic oils which poison adjacent soils and water.
Accordingly, numerous attempts have been made to develop processes to use or recycle scrap tires.
Scrap tires often contain several inorganic components such as zinc, sulfur and calcium which are impregnated into the rubbery portion of the tire. These inorganic components can be a hindrance to the recycling of the rubbery portion of the tires using various processes. For example, their removal is necessary when the tires are to be combusted in a conventional boiler since the inorganic components will cause air pollution and/or boiler scale build-up as well as interfering with various catalytic processes.
Many tires also include steel belts and bead wires for added strength and support. These belts and wires also must be removed from the scrap tires in order to permit effective recycling and use of the rubbery portion of the tire.
Accordingly, it would be a significant advancement in the art to provide a process for removing steel belts and other inorganic components from scrap tires to permit more effective recycling of the rubbery portion of the tires. It would be a further advancement to provide a process that converted tires into small particles for subsequent use. Such a process is disclosed and claimed herein.